DULUTH, Minn. — Hockey arenas across Minnesota are facing off against a big challenge: a chemical currently used in ice-making equipment at many arenas is harmful to the ozone layer so federal law is prompting expensive changes.

R-22 refrigerant runs beneath the ice at Northwoods Credit Union Arena in Cloquet and many others statewide, but imports of the chemical will be halted in 2020.

Finding a new way to freeze rinks could be too expensive for arenas like Cloquet's, WDIO-TV reported (http://bit.ly/1c86fLM ).

"The options ranged from about $1.2 million all the way up to $1.8 million," Rink Manager Justin Harriman said.

According to the Minnesota Ice Arena Managers Association, as many as 120 facilities could be affected statewide. The group has scheduled three regional workshops for next month in Mankato, South St. Paul and Virginia to discuss the R-22 phaseout, conversion options and costs, and legislative and funding options. Arena managers and lawmakers are discussing the possibility of state bonding money, as well as loans or grants.

Not every arena would face such a steep price tag. Costs could range from tens to hundreds of thousands of dollars, but the change will be widespread, and leaks could become expensive disasters as R-22 phases out and supplies tighten.

Harriman said small towns and hockey associations might not have the money to switch from R-22 to carbon dioxide or ammonia-based systems.

"If you had that many rinks go down I think you'd have some crying going on because you could shut down a lot of places if it wasn't available," Harriman said.